<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <style>
      html body {
        padding: 0px;
        margin: 0px;
      }
      .father {
        position: absolute;
        width: 100%;
        height: 100%;
        background-color: yellow;
        display: flex;
        justify-content: center;
        align-items: center;
      }
      .box{
        width: 200px;
        height: 200px;
        background-color: pink;
        border: 1px solid black;
      }

    </style>
    <div class="father">
      <div class="box">1</div>
      <!-- <div class="box">2</div> -->

    </div>
  </body>
</html>
